Biomedical subjects

J Shallo-Hoffmann

Publications and source records attributed to J Shallo-Hoffmann.

8 recordsLinked to original sources

PubMed1991

VEP projections in congenital nystagmus; VEP asymmetry in albinism: a comparison study.

Visual evoked potential (VEP) asymmetry in which a preponderance of nasal and temporal retina afferents project to the contralateral hemisphere after full-field monocular stimulation is considered specific to albinism. Some reports, however, suggest that patients with congenital nystagmus (CN) share the albino-like visual pathway anomaly. To examine the clinical specificity of albino misrouting, VEP topography was assessed in ten patients with congenital nystagmus and in ten age-matched albino patients. As an additional control, the VEP response profiles from eight albino patients with no nystagmus were also evaluated. The results are definitive; VEP contralateral asymmetry reflecting temporal retinal misprojection is evinced only in albino patients. Furthermore, ocular-motor instabilities in CN cannot be readily attributed to albino-type misrouted retinal-cortical projections.

Albinism↗

PubMed1991

[Physiologic and pathologic rebound nystagmus. Description and comparison].

Using a binocular, infrared charged coupled device (CCD), an eye tracker coupled with an Olivetti M24 PC (resolution up to 0.1 degrees, scanning with 80 frames/s), the eye movements of 20 normal individuals with normal visual acuity and binocular function were recorded to detect physiological endpoint (EPN) and rebound nystagmus (RN). Each subject was asked to fixate a target located in the primary position (PP) and after 5 s of recording time, to look at a target either 50 degrees to the right or left of the PP for approximately 20 s and then return for the last few seconds to the PP, EPN recordings were made with the room lights on and RN recordings were made both with the lights on and in total darkness. A forehead and chin rest with bite board were used. Twelve of the 20 subjects showed EPN and RN with the lights on. The 8 subjects that did not demonstrate EPN also showed no RN with the lights on. Recordings from all 20 subjects showed RN in darkness. No differences in amplitude were found between the abducted and adducted eyes. Although clear differences in the characteristics of gaze paretic or drug-related lateral gaze nystagmus and EPN have been found, no systematic differences in RN under lighted conditions had been observed between patients and normal subjects.

Adult↗

PubMed1991

[Subclinical eye movements as an indicator for inheritance of congenital nystagmus and central nervous system disease].

Clinically unaffected relatives of families with a history of either inherited congenital nystagmus or inherited neurogenic muscular and cerebellar atrophy underwent electrooculographic examination under three distinct test conditions. We found an increase in the number of square wave jerks, a higher than normal intensity score (defined in terms of frequency X amplitude of an involuntary saccade, unit: o/s) and nystagmus as compared with 110 normal individuals ranging in age from 21 to 89 years. These findings suggest a possible autosomal dominant mode of inheritance in the case study of congenital nystagmus presented. The results show abnormal eye movements in some family members from a family with inherited cerebellar degeneration with acquired nystagmus, suggesting that these family members are affected with the disorder. This study documents the rarely described observation of a connection between inherited cerebellar degeneration with inherited distal neurogenic muscular atrophy.

Adult↗

PubMed1990

A reexamination of end-point and rebound nystagmus in normals.

In order to detail the characteristics of end-point (EPN) and rebound nystagmus (RN), two series of experiments were performed with infrared oculography for measurement of horizontal eye movements. Experiment 1 consisted of EPN recordings during sustained lateral gaze (40 degrees and 50 degrees) in 20 normal subjects. Experiment 2 consisted of recordings of RN in 5 normal subjects. Nine of 20 subjects demonstrated a jerk EPN. EPN almost always appeared immediately and was sustained for 15-25 sec. In Experiment 2, RN occurred in 5 of the 5 subjects who demonstrated EPN. The mean amplitude of RN was always less than that of EPN, and decayed over a 5-10-sec time period. The experiment demonstrated that RN can be evoked in normals even when a fixation target, in a fully lit room, is present.

Adult↗

PubMed1990

[Artificial divergence surgery in congenital nystagmus].

The treatment possibilities for nystagmus have been expanded by the addition of the artificial divergence procedure. This paper presents a study on 26 nystagmus patients with and without anomalous head posture and good binocular function and with detailed pre- and postoperative electronystagmographic records. All patients had been treated by artificial divergence by means of a prism base out before the operation. Seventeen patients showed significant improvement after the artificial divergence procedure. In 3 patients this procedure had to be combined with the classic Kestenbaum procedure. In 6 patients, the effect of artificial divergence with prisms was not satisfactory; thus, the Kestenbaum procedure was necessary. This study proves the effectiveness of the artificial divergence procedure alone or in combination with other procedures for treatment of anomalous head posture and the improvement of visual acuity and binocular vision.

Adolescent↗

PubMed1990

Normal square wave jerks in differing age groups.

This report details the characteristics of normal square wave jerks (SWJ) over a broad age range. Sixty normally sighted subjects, categorized into three age groups (35-49 yr, 50-64 yr, and 65-89 yr) underwent electrooculographic (EOG) examination to investigate the characteristics of normal SWJ. The frequency, duration, and amplitude of SWJ per minute were calculated in three clinically used test conditions: 1) with a fixation point in a lighted room; 2) with eyes closed and 3) in darkness without a fixation point. Results were compared over age and conditions as well as with the scores of 50 normal young subjects (20-37 yr). SWJ were recorded in all conditions, with the highest number found with closed eyes and in darkness for all age groups. Contrary to earlier findings, no statistical differences in frequency of SWJ per minute due to age were observed. These findings describe a range of normalcy for these three EOG conditions from which pathology can be inferred.

Adult↗

PubMed1989

How normal are "normal" square wave jerks?

Fifty normally sighted young subjects underwent horizontal electro-oculographic (EOG) examination to investigate fixation stability of the saccadic system. The number of square wave jerks (SWJ) and saccades per minute were calculated in three clinically used test conditions: (1) with a fixation point; (2) in darkness; and (3) with eyes closed. SWJ were recorded in all conditions. The highest number of SWJ per minute were found in darkness and with closed eyes. The analysis of the findings shows a range of normalcy for these three clinically used EOG conditions from which pathology can be inferred.

Adult↗

PubMed1988

Fast-phase instabilities in normally sighted relatives of congenital nystagmus patients--autosomal dominant and x-chromosome recessive modes of inheritance.

Verification of inheritance in congenital nystagmus (CN) is only possible through the identification of more than one affected member in a family since in a single case there are no accurate clinical differentiations between "spontaneous" and inherited CN. We performed electronystagmographic examinations (ENG) to search for abnormal involuntary eye movements as a sign of heredity in seemingly unaffected members of CN families. ENG registrations were performed under three test conditions: (1) with the subject fixating a target, (2) with the room lights off and (3) with closed eyes. Fifty normally sighted individuals (group (a] underwent the test procedure to provide a baseline of normality. Five CN families (three dominant, two sex-linked recessive) were tested as group (b). The eye movement recordings were analysed in terms of nystagmus intensity (amplitude x frequency of the involuntary saccade). In every one of the five families, abnormalities in seemingly non-affected members could be demonstrated: in four families, fast-phase instabilities, in the fifth family a true (CN) (slow-phase instability). All certain gene carriers were diagnosed correctly by the ENG. These findings indicate a method for detecting slightly affected members in dominant pedigrees and female gene carriers in sex-linked mode of transmission.

Adult↗